Manganese oxide based catalyst and catalyst device for the removal of formaldehyde and volatile organic compounds

ABSTRACT

Disclosed herein are a catalyst composition, catalyst devices, and methods for removing formaldehyde, volatile organic compounds, and other pollutants from an air flow stream. The catalyst composition including manganese oxide, optionally one or more of alkali metals, alkaline earth metals, zinc, iron, binder, an inorganic oxide, or carbon.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 16/309,666, filed Dec. 13, 2018, which is aNational Phase entry of International Application No. PCT/US2017/036942,filed Jun. 12, 2017, which claims the benefit of priority of U.S.Provisional Patent Application No. 62/509,633, filed May 22, 2017, andU.S. Provisional Patent Application No. 62/357,007, filed Jun. 30, 2016,all which are hereby incorporated by reference herein in theirentireties.

TECHNICAL FIELD

The present disclosure relates to compositions, devices, and methods forair purification. More particularly, the disclosure relates to amanganese oxide based catalyst composition, catalyst device, method oftheir preparation, and methods for removing formaldehyde and volatileorganic compounds from air supplies.

BACKGROUND

Atmospheric pollution is a concern of increasing importance as thelevels of various atmospheric pollutants continue to increase. Oneprimary pollutant of concern is formaldehyde (HCOH). It is regarded as amajor indoor pollutant emitted from widely used building and decorativematerials. Long term exposure to formaldehyde is considered to becarcinogenic.

Several cities in China, including Shanghai, Hangzhou, Suzhou, Nanjing,Wuhan, Chongqing, and Chengdu, were inspected in 2011 by the IndoorEnvironment and the Health Branch of China Environmental ScienceInstitute with respect to the formaldehyde concentration presenttherein. Although the national standard sets a formaldehydeconcentration limit of 0.1 mg/m³, each of the cities inspected had aformaldehyde concentration level significantly higher than the nationallimit. The levels ranged from 15% to 40% higher than the nationalstandard.

There continues to be a need for devices, methods, and compositions thatcan effectively treat pollution from formaldehyde and other volatileorganic compounds (VOCs). These devices, methods, and compositionsshould exhibit long term performance, efficient manufacturingoperations, and reduced production costs.

SUMMARY

Disclosed herein are compositions, devices, and methods for purifying anair supply contaminated with formaldehyde and volatile organiccompounds. Also disclosed herein are methods for producing the catalystcompositions and catalyst devices.

In some embodiments, the invention is directed to a catalyst compositioncomprising manganese oxide. In some embodiments, the manganese oxide inthe catalyst composition may comprise cryptomelane, birnessite,vernadite, manganese oxide polymorph I, poorly crystalline cryptomelane,pyralusite, nsutite, amorphous manganese oxide, polymorphs thereof, ormixtures thereof.

In some embodiments, the catalyst composition comprises manganese oxide,wherein the manganese oxide exhibits an XRD spectrum in the range of 20to 80°2θ characterized by at least the following °2θ peaks andintensities:

Relative Intensity (%) as compared to the °2θ main peak 36-38   100%41-43  >20% 56-58  <50% 65-67  >20%.

In some embodiments, the catalyst composition comprises manganese oxide,wherein the manganese oxide exhibits an XRD spectrum in the range of 20to 80°2θ characterized by the following °2θ peaks and intensities:

Relative Intensity (%) as compared to the °2θ main peak 36-38   100%41-43  >20% 56-58  <50% 65-67  >20%;and wherein other peaks may be present at a relative intensity lowerthan 20%.

In other embodiments, the catalyst composition comprises manganeseoxide, wherein the manganese oxide exhibits an XRD spectrum in the rangeof 20 to 80°2θ characterized solely by the following °2θ peaks andintensities:

Relative Intensity (%) as compared to the °2θ main peak 36-38   100%41-43  >20% 56-58  <50% 65-67  >20%.

In some embodiments, the catalyst composition may further comprise oneor more of an alkali metal, an alkaline earth metal, zinc, iron, aninorganic oxide, a binder, activated carbon, or combinations thereof.

In some embodiments, the catalyst composition may be in the form ofextrudates. In other embodiments, the catalyst composition may be in aform of a coating layer disposed on a solid substrate.

In some embodiments, the catalyst composition may comprises a BETsurface area ranging from about 5 m²/g to about 2000 m²/g, from about 10m²/g to about 2000 m²/g, from about 15 m²/g to about 2000 m²/g, fromabout 20 m²/g to about 2000 m²/g, from about 25 m²/g to about 2000 m²/g,from about 30 m²/g to about 2000 m²/g, from about 35 m²/g to about 2000m²/g, from about 40 m²/g to about 2000 m²/g, from about 45 m²/g to about2000 m²/g, from about 5 m²/g to about 1500 m²/g, from about 5 m²/g toabout 1300 m²/g, from about 5 m²/g to about 1100 m²/g, from about 5 m²/gto about 1000 m²/g, from about 5 m²/g to about 750 m²/g, from about 5m²/g to about 500 m²/g, from about 5 m²/g to about 400 m²/g, from about5 m²/g to about 300 m²/g, from about 5 m²/g to about 200 m²/g, fromabout 5 m²/g to about 150 m²/g, from about 5 m²/g to about 100 m²/g,from about 5 m²/g to about 75 m²/g, from about 5 m²/g to about 50 m²/g,from about 5 m²/g to about 30 m²/g, from about 50 m²/g to about 2000m²/g, from about 100 m²/g to about 2000 m²/g, from about 150 m²/g toabout 2000 m²/g, from about 170 m²/g to about 2000 m²/g, from about 50m²/g to about 1500 m²/g, from about 100 m²/g to about 1500 m²/g, fromabout 150 m²/g to about 1500 m²/g, from about 170 m²/g to about 1500m²/g, from about 50 m²/g to about 1300 m²/g, from about 100 m²/g toabout 1300 m²/g, from about 150 m²/g to about 1300 m²/g, from about 170m²/g to about 1300 m²/g, from about 50 m²/g to about 1100 m²/g, fromabout 100 m²/g to about 1100 m²/g, from about 150 m²/g to about 1100m²/g, from about 170 m²/g to about 1100 m²/g, from about 50 m²/g toabout 1000 m²/g, from about 100 m²/g to about 1000 m²/g, from about 150m²/g to about 1000 m²/g, from about 170 m²/g to about 1000 m²/g, fromabout 100 m²/g to about 500 m²/g, from about 100 m²/g to about 400 m²/g,from about 100 m²/g to about 350 m²/g, from about 100 m²/g to about 300m²/g, or from about 100 m²/g to about 250 m²/g, from about 150 m²/g toabout 500 m²/g, from about 150 m²/g to about 400 m²/g, from about 150m²/g to about 350 m²/g, from about 150 m²/g to about 300 m²/g, or fromabout 150 m²/g to about 250 m²/g. In some embodiments, the BET surfacearea ranges from about 70 m²/g to 150 m²/g, from about 70 m²/g to 125m²/g, from about 70 m²/g to 100 m²/g, from about 50 m²/g to 150 m²/g,from about 50 m²/g to 125 m²/g, from about 50 m²/g to 100 m²/g, fromabout 50 m²/g to 80 m²/g, from about 25 m²/g to 150 m²/g, from about 25m²/g to 125 m²/g, from about 25 m²/g to 100 m²/g, from about 25 m²/g to70 m²/g, from about 10 m²/g to 150 m²/g, from about 10 m²/g to 125 m²/g,from about 10 m²/g to 100 m²/g, from about 10 m²/g to 70 m²/g, fromabout 10 m²/g to 50 m²/g, from about 5 m²/g to 150 m²/g, from about 5m²/g to 125 m²/g, from about 5 m²/g to 100 m²/g, from about 5 m²/g to 70m²/g, from about 5 m²/g to 50 m²/g, from about 5 m²/g to 25 m²/g, orfrom about 5 m²/g to 10 m²/g.

In some embodiments, the catalyst composition may be porous with porevolumes ranging from about 0.3 mL/g to about 1.5 mL/g, from about 0.3mL/g to about 1.0 mL/g, from about 0.3 mL/g to about 0.9 mL/g or fromabout 0.5 mL/g to about 0.75 mL/g.

In some embodiments, the invention is directed to a catalyst device forpurifying an air supply. In some embodiments, the device comprises acatalyst or a catalytic adsorbent. The catalyst device may comprise ahousing and a catalyst composition disposed in the housing. The catalystcomposition in the catalyst device may be any of the catalystcompositions disclosed herein. The catalyst device may further comprisean inlet port configured to receive unpurified air into an interior ofthe housing and an outlet port configured to deliver purified air fromthe housing. The catalyst device may be configured to contact theunpurified air with the catalyst composition, such that the formaldehydeand/or the volatile organic compounds present in the unpurified air areremoved upon contact with the catalyst composition.

In some embodiments, the invention is directed to a method of preparingan extruded catalyst. The method for preparing an extruded catalyst maycomprise mixing manganese oxide, water, and optionally one or more of analkali metal, an alkaline earth metal, zinc, iron, an inorganic oxide(such as rare earth oxides), a binder, activated carbon, or combinationsthereof, to form an extrudable paste. The method may further compriseextruding the paste to form any of the catalyst compositions disclosedherein.

In other embodiments, the invention is directed to a method of preparinga catalyst composition disposed onto a substrate. The method forpreparing a catalyst composition disposed onto a substrate may comprisedispersing manganese and optionally one or more of an alkali metal, analkaline earth metal, zinc, iron, an inorganic oxide, a binder,activated carbon, or combinations thereof, in water to form a catalystcomposition slurry. The method may further comprise coating the catalystcomposition onto the substrate. The catalyst composition disposed on thesubstrate may be any of the catalyst compositions disclosed herein.

In some embodiments, the invention is directed to a method for purifyingan air flow stream by contacting the unpurified air flow stream with acatalyst composition according to the invention to produce a purifiedair flow stream.

The catalyst composition, catalyst device, and methods for purifying airstreams according to the invention may all be configured to remove oneor more of formaldehyde, ozone, carbon monoxide, nitrogen oxides,amines, sulfur compounds, thiols, chlorinated hydrocarbons, or volatileorganic compounds from an unpurified air supply.

As used herein, the terms “stream” or “flow” broadly refer to anyflowing gas that may contain solids (e.g., particulates), liquids (e.g.,vapor), and/or gaseous mixtures.

The terms “unpurified air” or “unpurified air stream” refers to anystream that contains one or more pollutants at a concentration orcontent at or above a level that is perceived as nuisance or isconsidered to have adverse effects on human health (including short termand/or long term effects). For example, in some embodiments, a streamthat contains formaldehyde at a concentration greater than 0.5 partformaldehyde per million parts of air stream calculated as an eight hourtime weighted average concentration pursuant to “action level” standardsset forth by the Occupational Safety & Health Administration is anunpurified air stream. In some embodiments, a stream that containsformaldehyde at a concentration greater than 0.08 part formaldehyde permillion parts of air stream calculated as an eight hour time weightedaverage concentration pursuant to national standards in China is anunpurified air stream. Unpurified air may include, but is not limitedto, formaldehyde, ozone, carbon monoxide (CO), volatile organiccompounds (VOCs), methyl bromide, water, amines, and nitrogen oxides.

The term “VOCs” refers to organic chemical molecules having an elevatedvapor pressure at room temperature. Such chemical molecules have a lowboiling point and a large number of the molecules evaporate and/orsublime at room temperature, thereby transitioning from a liquid orsolid phase to a gas phase. Common VOCs include, but are not limited to,benzene, toluene, xylene, ethylbenzene, styrene, propane, hexane,cyclohexane, limonene, pinene, acetaldehyde, hexaldehyde, ethyl acetate,butanol, and the like.

The terms “purified air” or “purified air stream” refer to any streamthat contains one or more pollutants at a concentration or content thatis lower than the concentration or content of that one or morepollutants in the unpurified air stream.

The term “substrate” refers to a material (e.g., a metal, semi-metal,semi-metal oxide, metal oxide, polymeric, ceramic) onto or into whichthe catalyst is placed. In some embodiments, the substrate may be in theform of a solid surface having a washcoat containing a plurality ofcatalytic particles. A washcoat may be formed by preparing a slurrycontaining a specified solids content (e.g., 30-50% by weight) ofcatalytic particles, which is then coated onto a substrate and dried toprovide a washcoat layer. In some embodiments, the substrate may beporous and the washcoat may be deposited outside and/or inside thepores.

The term “nitrogen oxide” refers to compounds containing nitrogen andoxygen including but not limited to, nitric oxide, nitrogen dioxide,nitrous oxide, nitrosylazide, ozatetrazole, dinitrogen trioxide,dinitrogen tetroxide, dinitrogen pentoxide, trinitramide, nitrite,nitrate, nitronium, nitrosonium, peroxonitrite, or combinations thereof.

The term “sulfur compounds” refers to compounds containing sulfurincluding but not limited to sulfur oxides (sulfur monoxide, sulfurdioxide, sulfur trioxide, disulfur monoxide, disulfur dioxide), hydrogensulfide, or combinations thereof.

The term “manganese oxide polymorph I” refers to a manganese oxide in asemi-crystalline phase exhibiting an XRD spectrum in the range of 20 to80°2θ characterized by the following °2θ peaks and intensities. Cu_(kα)radiation was used in the analysis with generator settings of 45 kV and40 mA.

°2θ Relative Intensity (%) 36-38   100% 41-43  >20% 56-58  <50% 65-67 >20%

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present disclosure, their nature,and various advantages will become more apparent upon consideration ofthe following detailed description, taken in conjunction with theaccompanying drawings, in which:

FIG. 1A depicts an x-ray diffraction pattern for cryptomelane manganeseoxide;

FIG. 1B depicts an x-ray diffraction pattern for manganese oxidepolymorph I;

FIG. 1C depicts an x-ray diffraction pattern for poorly crystallinecryptomelane;

FIG. 2 depicts an illustrative process for producing a catalystcomposition in accordance with an embodiment;

FIG. 3 depicts an illustrative process for producing a catalystcomposition in accordance with an embodiment;

FIG. 4 depicts a one pass test schematic diagram for air purification inaccordance with an embodiment;

FIG. 5 depicts a system test schematic diagram for air purification inaccordance with an embodiment;

FIG. 6 depicts an illustrative control process for air purification inaccordance with an embodiment disclosed herein;

FIG. 7 depicts an illustrative test apparatus in accordance with anembodiment disclosed herein;

FIG. 8 is a plot depicting formaldehyde and toluene conversion forvarious catalyst compositions described in examples 1-13;

FIG. 9 is a plot depicting formaldehyde conversion for various catalystcompositions described in examples 14-16; and

FIG. 10 is a plot depicting formaldehyde conversion for various catalystcompositions described in examples 24-27.

DETAILED DESCRIPTION

The present disclosure relates to catalyst compositions, catalystdevices, methods of their preparation, and methods of their use fortreating a flow of ambient air by converting and/or removingcontaminants therefrom. Contaminants may comprise one or more offormaldehyde, ozone, carbon monoxide, nitrous oxide, amines, sulfurcompounds, thiols, chlorinated hydrocarbons, or volatile organiccompounds in unpurified air flow streams. The contaminants may beconverted into less harmful compounds such as oxygen, carbon dioxide andwater vapor. The catalyst composition may be manganese oxide based andmay further comprise one or more of an alkali metal, an alkaline earthmetal, zinc, iron, an inorganic oxide, a binder, activated carbon, orcombinations thereof. The catalyst composition may be in the form of aplurality of extruded particles or may be disposed on a substrate as acoating layer. The catalyst composition may be disposed in a housing toform a catalyst device which may further comprise and inlet and anoutlet port such that unpurified air enters the catalyst device throughthe inlet port, the unpurified air is contacted with the catalystcomposition in the housing, thereby forming a purified air stream whichmay exit the catalyst device through an outlet port. The purified airmay contain reduced levels of contaminants.

Catalyst Composition Embodiments

In some embodiments, the present invention may be directed to a catalystcomposition comprising manganese oxide, wherein the catalyst compositioncomprises a BET surface area ranging from about from about 5 m²/g toabout 2000 m²/g, from about 10 m²/g to about 2000 m²/g, from about 15m²/g to about 2000 m²/g, from about 20 m²/g to about 2000 m²/g, fromabout 25 m²/g to about 2000 m²/g, from about 30 m²/g to about 2000 m²/g,from about 35 m²/g to about 2000 m²/g, from about 40 m²/g to about 2000m²/g, from about 45 m²/g to about 2000 m²/g, from about 5 m²/g to about1500 m²/g, from about 5 m²/g to about 1300 m²/g, from about 5 m²/g toabout 1100 m²/g, from about 5 m²/g to about 1000 m²/g, from about 5 m²/gto about 750 m²/g, from about 5 m²/g to about 500 m²/g, from about 5m²/g to about 400 m²/g, from about 5 m²/g to about 300 m²/g, from about5 m²/g to about 200 m²/g, from about 5 m²/g to about 150 m²/g, fromabout 5 m²/g to about 100 m²/g, from about 5 m²/g to about 75 m²/g, fromabout 5 m²/g to about 50 m²/g, from about 5 m²/g to about 30 m²/g, fromabout 50 m²/g to about 2000 m²/g, from about 100 m²/g to about 2000m²/g, from about 150 m²/g to about 2000 m²/g, from about 170 m²/g toabout 2000 m²/g, from about 50 m²/g to about 1500 m²/g, from about 100m²/g to about 1500 m²/g, from about 150 m²/g to about 1500 m²/g, fromabout 170 m²/g to about 1500 m²/g, from about 50 m²/g to about 1300m²/g, from about 100 m²/g to about 1300 m²/g, from about 150 m²/g toabout 1300 m²/g, from about 170 m²/g to about 1300 m²/g, from about 50m²/g to about 1100 m²/g, from about 100 m²/g to about 1100 m²/g, fromabout 150 m²/g to about 1100 m²/g, from about 170 m²/g to about 1100m²/g, from about 50 m²/g to about 1000 m²/g, from about 100 m²/g toabout 1000 m²/g, from about 150 m²/g to about 1000 m²/g, from about 170m²/g to about 1000 m²/g, from about 100 m²/g to about 500 m²/g, fromabout 100 m²/g to about 400 m²/g, from about 100 m²/g to about 350 m²/g,from about 100 m²/g to about 300 m²/g, or from about 100 m²/g to about250 m²/g, from about 150 m²/g to about 500 m²/g, from about 150 m²/g toabout 400 m²/g, from about 150 m²/g to about 350 m²/g, from about 150m²/g to about 300 m²/g, or from about 150 m²/g to about 250 m²/g. Insome embodiments, the BET surface area ranges from about 70 m²/g to 150m²/g, from about 70 m²/g to 125 m²/g, from about 70 m²/g to 100 m²/g,from about 50 m²/g to 150 m²/g, from about 50 m²/g to 125 m²/g, fromabout 50 m²/g to 100 m²/g, from about 50 m²/g to 80 m²/g, from about 25m²/g to 150 m²/g, from about 25 m²/g to 125 m²/g, from about 25 m²/g to100 m²/g, from about 25 m²/g to 70 m²/g, from about 10 m²/g to 150 m²/g,from about 10 m²/g to 125 m²/g, from about 10 m²/g to 100 m²/g, fromabout 10 m²/g to 70 m²/g, from about 10 m²/g to 50 m²/g, from about 5m²/g to 150 m²/g, from about 5 m²/g to 125 m²/g, from about 5 m²/g to100 m²/g, from about 5 m²/g to 70 m²/g, from about 5 m²/g to 50 m²/g,from about 5 m²/g to 25 m²/g, or from about 5 m²/g to 10 m²/g. BETsurface area, as referenced herein, is measured using N₂ as theadsorbate. The surface area is measured on an Ankersmit QuantachromeAutosorb-6 apparatus, after degassing samples at 180° C. to a pressureof 3.3 Pa (25 mTorr).

The manganese oxide in the catalyst composition may comprisecryptomelane, birnessite, vernadite, manganese oxide polymorph I,pyrolusite, nsutite, poorly crystalized cryptomelane, amorphousmanganese oxide, polymorphs thereof, or mixtures thereof. The manganeseoxide in the catalyst composition may be 100% crystalline, 100%amorphous, or partially crystalline and partially amorphous. X-RayDiffraction (XRD) technique is utilized to determine the crystallinityof the manganese oxide in the catalyst composition. A catalystcomposition may be deemed completely amorphous if a peak is absent fromthe XRD profile. Alternatively, a catalyst composition may be deemed atleast partially crystalline if some peaks are observed in its XRDprofile. Each type of manganese oxide may have a corresponding XRDprofile. For example, cryptomelane manganese oxide may exhibit an XRDpattern illustrated in FIG. 1A; manganese oxide polymorph I may exhibitan XRD pattern illustrated in FIG. 1B; and a poorly crystallinecryptomelane manganese oxide may exhibit an XRD pattern illustrated inFIG. 1C.

When manganese oxide polymorph I is present in the catalyst composition,in some embodiments, the manganese oxide may exhibit an XRD pattern inthe range of 20 to 80°2θ having at least the following °2θ peaks andintensities:

Relative Intensity (%) as compared to the °2θ main peak 36-38   100%41-43  >20% 56-58  <50% 65-67  >20%.

In other embodiments, when manganese oxide polymorph I is present in thecatalyst composition, the manganese oxide may exhibit an XRD pattern inthe range of 20 to 80°2θ having solely the following °2θ peaks andintensities:

Relative Intensity (%) as compared to the °2θ main peak 36-38   100%41-43  >20% 56-58  <50% 65-67  >20%.

In yet other embodiments, when manganese oxide polymorph I is present inthe catalyst composition, the manganese oxide may exhibit an XRD patternin the range of 20 to 80°2θ having the following °2θ peaks andintensities:

Relative Intensity (%) as compared to the °2θ main peak 36-38   100%41-43  >20% 56-58  <50% 65-67  >20%wherein if additional peaks are present, the relative intensity of theadditional peaks is less than 20%.

In some embodiments, the manganese oxide in the catalyst composition(regardless of the form it is in) may be present in an amount rangingfrom about 5 wt % to about 100 wt %, from about 10 wt % to about 90 wt%, or from about 15 wt % to about 75 wt %, from about 40 wt % to about90 wt %, or from about 45 wt % to about 75 wt % based on total weight ofthe catalyst composition.

In some embodiments, the catalyst composition may further comprise abinder. In some embodiments, the binder may comprise alumina. In someembodiments, the binder may comprise a polymeric binder. In someembodiments, the binder may be one or more of alumina, zirconia, silica,aluminum phyllosilicate clay such as bentonite, or mixtures thereof. Insome embodiments, the binders with low glass transition temperature mayresult in more flexible or less brittle catalyst compositions and may bepreferred. In some embodiments, the chosen binder may be one that with10 weight % binder (based on the total weight of the catalystcomposition) enables 70% of the catalyst composition's activity ascompared to the activity of a catalyst composition without a binder.

Examples of additional suitable binders may include, but not limited to,alumina sol, boehmite, silica sol, titania sol, zirconium acetate, andcolloidal ceria sol. Examples of polymer binders may include but not belimited to, polyethylene, polypropylene, polyolefin copolymers,polyisoprene, polybutadiene, polybutadiene copolymers, chlorinatedrubber, nitrile rubber, polychloroprene, ethylene-propylene-dieneelastomers, polystyrene, polyacrylate, polymethacrylate,polyacrylonitrile, poly(vinyl esters), poly(vinyl halides), polyamides,cellulosic polymers, polyimides, acrylics, vinyl acrylics, styreneacrylics, polyvinyl alcohols, thermoplastic polyesters, thermosettingpolyesters, poly(phenylene oxide), poly(phenylene sulfide), fluorinatedpolymers such as poly(tetrafluoroethylene), polyvinylidene fluoride,poly(vinlyfluoride) and chloro/fluoro copolymers such as ethylenechlorotrifluoroethylene copolymer, polyamide, phenolic resins,polyurethane, acrylic/styrene acrylic copolymer latex and siliconepolymers.

In some embodiments, the binder in the catalyst composition may bepresent in an amount equal to about 60 wt % or less, equal to about 50wt % or less, or equal to about 40 wt % or less, based on total weightof the catalyst composition.

In some embodiments, the catalyst composition may further compriseinorganic oxides. The inorganic oxides may be one or more of ceria,zirconia, silica, titania, alumina, iron, lanthanum, praseodymium,samarium, or mixtures thereof. In some embodiments, the inorganic oxidemay be ceria. In some embodiments, the inorganic oxide may be zirconia.In some embodiments, the inorganic oxide may be silica.

In some embodiments, the inorganic oxide in the catalyst composition maybe present in an amount equal to about 60 wt % or less, equal to about50 wt % or less, equal to about 40 wt % or less based on total weight ofthe catalyst composition. In some embodiments, inorganic oxides mayinclude rare earth oxides.

In some embodiments, the catalyst composition may further comprise oneor more of an alkali metal, an alkaline earth metal, zinc, iron, ormixtures thereof. The one or more of an alkali metal, an alkaline earthmetal, zinc, iron, or mixtures thereof may be present in the catalystcomposition in an amount equal to about 10 wt % or less, equal to about5 wt % or less, or equal to about 2 wt % or less based on the totalweight of the catalyst composition.

In some embodiments, the catalyst composition may be in the form of aplurality of distinct extruded particles. The plurality of extrudedparticles may be of various shapes, such as, pellets, beads, extrudates,rings, spheres, cylinders, trilobe, and quadralobe shaped pieces. Theplurality of extruded particles may vary in size, for example, theparticles may have a mean diameter ranging from about 1 millimeter toabout 15 millimeter.

In other embodiments, the catalyst composition may be disposed on asolid substrate, thereby forming a catalyst system. The loading of thecatalyst composition on the substrate may range from about 0.5 g/in³ toabout 4 g/in³. For example, the catalyst composition may be coated ontoa solid substrate and may form a single coat of catalytic material onthe solid substrate or a plurality of layers of catalytic material onthe solid substrate. If a plurality of layers of catalytic material iscoated on the solid substrate, the layers may vary in their compositionsor alternatively all catalyst layers may have the same composition. Insome embodiments, the solid substrate may comprise a polymer substrate,a ceramic substrate, a metallic substrate, a foam substrate, a papersubstrate, or mixtures thereof.

In some embodiments, the substrate may be a nonwoven filter, a paperfilter, a ceramic filter, or a fibrous filter. In some embodiments, thesubstrate may be a metallic foam substrate, a ceramic foam substrate, ora polymeric foam substrate. In some embodiments, the substrate may be ametallic monolithic substrate, a ceramic monolithic substrate, a papermonolithic substrate, a polymer monolithic substrate, or a ceramic fibermonolithic substrate. In some embodiments, the substrate may be an HVACduct, an air filter, or a louver surface. In some embodiments, thesubstrate may be a portable air filter, or a filter disposed in avehicle selected from the group consisting of motor vehicles, railedvehicle, watercrafts, aircrafts, and space crafts. In some embodimentsthe substrate may be absent altogether.

In some embodiments, the catalyst composition may further comprise asorbent such as carbon, impregnated (treated) carbon, metal organicframeworks (MOFs), zeolites, or combinations thereof. In someembodiments, the catalyst composition may comprise activated carbon. Insome embodiments, the sorbent may have optimal parameters, such as BETsurface area, pore volume, bulk density, mass, volume, and diameter thatwill increase the sorbent's affinity to certain contaminants.

In some embodiments, the sorbent may comprise MOFs in a form of apowder, pellets, extrudates, granulates, or a free-standing film. Incertain embodiments, the MOF is in the form of MOF particles. In someembodiments the adsorbent material is a zeolitic material having aframework structure composed of YO₂ and X₂O₃, in which Y is atetravalent element and X is a trivalent element. In one embodiment Y isselected from the group consisting of Si, Sn, Ti, Zr, Ge, andcombinations of two or more thereof. In one embodiment Y is selectedfrom the group consisting of Si, Ti, Zr, and combinations of two or morethereof. In one embodiment Y is Si and/or Sn. In one embodiment Y is Si.In one embodiment X is selected from the group consisting of Al, B, In,Ga, and combinations of two or more thereof. In one embodiment X isselected from the group consisting of Al, B, In, and combinations of twoor more thereof. In one embodiment X is Al and/or B. In one embodiment Xis Al. In certain embodiments the zeolite is in a form of particles,pellets, extrudates, granulates, a powder, or a free-standing film. Incertain embodiments the zeolite is in a form of zeolite particles.

In certain embodiments, the sorbent may be activated. The activation mayinclude subjecting the sorbent to various conditions including, but notlimited to, ambient temperature, vacuum, an inert gas flow, or anycombination thereof, for sufficient time to activate the sorbentmaterial.

In some embodiments, the catalyst composition is configured to removeone or more of formaldehyde, ozone, carbon monoxide, nitrogen oxides,amines, sulfur compounds, thiols, chlorinated hydrocarbons, or volatileorganic compounds from an unpurified air supply.

In some embodiments, the catalyst composition may be porous and havepore volumes ranging from about 0.3 mL/g to about 1.5 mL/g, from about0.3 mL/g to about 1.0 mL/g, from about 0.3 mL/g to about 0.9 mL/g, fromabout 0.5 mL/g to about 0.9 mL/g, or from about 0.5 mL/g to about 0.75mL/g. Pore volume, as discussed herein, may refer to an average porevolume as measured by nitrogen porosimetry using, for example, the BJH(Barrett, Joyner and Halenda) method, or by mercury intrusionporosimetry. In the present disclosure, average pore volume is measuredusing the BJH method unless otherwise specified.

In some embodiments, the catalyst composition may consist essentially ofone of the following: manganese oxide only, manganese oxide and a binderonly, manganese oxide and an inorganic oxide only, or manganese oxidewith a binder and an activated carbon only, and have a BET surface areafrom about 5 m²/g to about 2000 m²/g, from about 10 m²/g to about 2000m²/g, from about 15 m²/g to about 2000 m²/g, from about 20 m²/g to about2000 m²/g, from about 25 m²/g to about 2000 m²/g, from about 30 m²/g toabout 2000 m²/g, from about 35 m²/g to about 2000 m²/g, from about 40m²/g to about 2000 m²/g, from about 45 m²/g to about 2000 m²/g, fromabout 5 m²/g to about 1500 m²/g, from about 5 m²/g to about 1300 m²/g,from about 5 m²/g to about 1100 m²/g, from about 5 m²/g to about 1000m²/g, from about 5 m²/g to about 750 m²/g, from about 5 m²/g to about500 m²/g, from about 5 m²/g to about 400 m²/g, from about 5 m²/g toabout 300 m²/g, from about 5 m²/g to about 200 m²/g, from about 5 m²/gto about 150 m²/g, from about 5 m²/g to about 100 m²/g, from about 5m²/g to about 75 m²/g, from about 5 m²/g to about 50 m²/g, from about 5m²/g to about 30 m²/g, from about 50 m²/g to about 2000 m²/g, from about100 m²/g to about 2000 m²/g, from about 150 m²/g to about 2000 m²/g,from about 170 m²/g to about 2000 m²/g, from about 50 m²/g to about 1500m²/g, from about 100 m²/g to about 1500 m²/g, from about 150 m²/g toabout 1500 m²/g, from about 170 m²/g to about 1500 m²/g, from about 50m²/g to about 1300 m²/g, from about 100 m²/g to about 1300 m²/g, fromabout 150 m²/g to about 1300 m²/g, from about 170 m²/g to about 1300m²/g, from about 50 m²/g to about 1100 m²/g, from about 100 m²/g toabout 1100 m²/g, from about 150 m²/g to about 1100 m²/g, from about 170m²/g to about 1100 m²/g, from about 50 m²/g to about 1000 m²/g, fromabout 100 m²/g to about 1000 m²/g, from about 150 m²/g to about 1000m²/g, from about 170 m²/g to about 1000 m²/g, from about 100 m²/g toabout 500 m²/g, from about 100 m²/g to about 400 m²/g, from about 100m²/g to about 350 m²/g, from about 100 m²/g to about 300 m²/g, or fromabout 100 m²/g to about 250 m²/g, from about 150 m²/g to about 500 m²/g,from about 150 m²/g to about 400 m²/g, from about 150 m²/g to about 350m²/g, from about 150 m²/g to about 300 m²/g, or from about 150 m²/g toabout 250 m²/g. In some embodiments, the BET surface area ranges fromabout 70 m²/g to 150 m²/g, from about 70 m²/g to 125 m²/g, from about 70m²/g to 100 m²/g, from about 50 m²/g to 150 m²/g, from about 50 m²/g to125 m²/g, from about 50 m²/g to 100 m²/g, from about 50 m²/g to 80 m²/g,from about 25 m²/g to 150 m²/g, from about 25 m²/g to 125 m²/g, fromabout 25 m²/g to 100 m²/g, from about 25 m²/g to 70 m²/g, from about 10m²/g to 150 m²/g, from about 10 m²/g to 125 m²/g, from about 10 m²/g to100 m²/g, from about 10 m²/g to 70 m²/g, from about 10 m²/g to 50 m²/g,from about 5 m²/g to 150 m²/g, from about 5 m²/g to 125 m²/g, from about5 m²/g to 100 m²/g, from about 5 m²/g to 70 m²/g, from about 5 m²/g to50 m²/g, from about 5 m²/g to 25 m²/g, or from about 5 m²/g to 10 m²/g.

In some embodiments, any of the above catalyst composition mayoptionally further consist essentially of one or more of an alkalimetal, an alkaline earth metal, zinc, or iron.

Catalyst Device Embodiments

In some embodiments, the catalyst device may comprise a housing and acatalyst composition disposed in the housing, wherein the catalystcomposition comprises manganese oxide, and wherein the catalystcomposition comprises a BET surface area ranging from about 5 m²/g toabout 2000 m²/g, from about 10 m²/g to about 2000 m²/g, from about 15m²/g to about 2000 m²/g, from about 20 m²/g to about 2000 m²/g, fromabout 25 m²/g to about 2000 m²/g, from about 30 m²/g to about 2000 m²/g,from about 35 m²/g to about 2000 m²/g, from about 40 m²/g to about 2000m²/g, from about 45 m²/g to about 2000 m²/g, from about 5 m²/g to about1500 m²/g, from about 5 m²/g to about 1300 m²/g, from about 5 m²/g toabout 1100 m²/g, from about 5 m²/g to about 1000 m²/g, from about 5 m²/gto about 750 m²/g, from about 5 m²/g to about 500 m²/g, from about 5m²/g to about 400 m²/g, from about 5 m²/g to about 300 m²/g, from about5 m²/g to about 200 m²/g, from about 5 m²/g to about 150 m²/g, fromabout 5 m²/g to about 100 m²/g, from about 5 m²/g to about 75 m²/g, fromabout 5 m²/g to about 50 m²/g, from about 5 m²/g to about 30 m²/g, fromabout 50 m²/g to about 2000 m²/g, from about 100 m²/g to about 2000m²/g, from about 150 m²/g to about 2000 m²/g, from about 170 m²/g toabout 2000 m²/g, from about 50 m²/g to about 1500 m²/g, from about 100m²/g to about 1500 m²/g, from about 150 m²/g to about 1500 m²/g, fromabout 170 m²/g to about 1500 m²/g, from about 50 m²/g to about 1300m²/g, from about 100 m²/g to about 1300 m²/g, from about 150 m²/g toabout 1300 m²/g, from about 170 m²/g to about 1300 m²/g, from about 50m²/g to about 1100 m²/g, from about 100 m²/g to about 1100 m²/g, fromabout 150 m²/g to about 1100 m²/g, from about 170 m²/g to about 1100m²/g, from about 50 m²/g to about 1000 m²/g, from about 100 m²/g toabout 1000 m²/g, from about 150 m²/g to about 1000 m²/g, from about 170m²/g to about 1000 m²/g, from about 100 m²/g to about 500 m²/g, fromabout 100 m²/g to about 400 m²/g, from about 100 m²/g to about 350 m²/g,from about 100 m²/g to about 300 m²/g, or from about 100 m²/g to about250 m²/g, from about 150 m²/g to about 500 m²/g, from about 150 m²/g toabout 400 m²/g, from about 150 m²/g to about 350 m²/g, from about 150m²/g to about 300 m²/g, or from about 150 m²/g to about 250 m²/g. Insome embodiments, the BET surface area ranges from about 70 m²/g to 150m²/g, from about 70 m²/g to 125 m²/g, from about 70 m²/g to 100 m²/g,from about 50 m²/g to 150 m²/g, from about 50 m²/g to 125 m²/g, fromabout 50 m²/g to 100 m²/g, from about 50 m²/g to 80 m²/g, from about 25m²/g to 150 m²/g, from about 25 m²/g to 125 m²/g, from about 25 m²/g to100 m²/g, from about 25 m²/g to 70 m²/g, from about 10 m²/g to 150 m²/g,from about 10 m²/g to 125 m²/g, from about 10 m²/g to 100 m²/g, fromabout 10 m²/g to 70 m²/g, from about 10 m²/g to 50 m²/g, from about 5m²/g to 150 m²/g, from about 5 m²/g to 125 m²/g, from about 5 m²/g to100 m²/g, from about 5 m²/g to 70 m²/g, from about 5 m²/g to 50 m²/g,from about 5 m²/g to 25 m²/g, or from about 5 m²/g to 10 m²/g. Thecatalyst composition disposed within the housing may be any of thecatalyst compositions disclosed herein. For example, in someembodiments, the catalyst device may comprise a housing and a catalystcomposition disposed in the housing, wherein the catalyst compositioncomprises manganese oxide, a binder, and activated carbon.

The catalyst device may further comprise an inlet port configured toreceive unpurified air into an interior of the housing and an outletport configured to deliver purified air from the housing. The catalystdevice may be configured to contact the unpurified air with the catalystcomposition disposed in the housing.

The catalyst composition, whether as a plurality of extruded particlesor as part of a catalyst system in which the catalyst composition iscoated onto the solid substrate, is arranged in the housing of thecatalyst device, such that when an air flow is introduced into the aircatalyst device, the catalyst particles or catalyst coating layercontacts the air flow and either removes formaldehyde or convertsformaldehyde in the air flow into carbon dioxide and water. In certainembodiments, other pollutants and/or contaminants in the air flow may beremoved or converted into harmless or less harmful chemical species uponcontact with the catalyst particle(s) or catalyst layer(s).

In some embodiments, the present invention is directed to a catalystdevice for purifying an air supply from contaminants such asformaldehyde, ozone, carbon monoxide, nitrogen oxides, amines, sulfurcompounds, thiols, chlorinated hydrocarbons, or volatile organiccompounds. The formaldehyde content in the unpurified air streamentering the catalyst device may range from about 1 ppb to about 50 ppm.The ozone content in the unpurified air stream entering the catalystdevice may range from about 1 ppb to about 2 ppm. The volatile organiccompounds content in the unpurified air stream entering the catalystdevice may range from about 1 ppb to about 0.5 vol. %. The contaminantscontent in the unpurified air stream may also be referred herein asinitial contaminant content, e.g., initial formaldehyde content, initialozone content, initial volatile organic compound content, and so on.

In some embodiments, the contaminants present in the unpurified airstream (such as formaldehyde, ozone, carbon monoxide, nitrogen oxides,amines, sulfur compounds, thiols, chlorinated hydrocarbons, or volatileorganic compounds) may be removed upon contact of the unpurified airstream with the catalyst composition disposed in the catalyst device.For example, the unpurified air stream may have an initial formaldehydecontent, and the purified air stream exiting from the catalyst devicemay have a final formaldehyde content that is less than the initialformaldehyde content.

The final formaldehyde content of the purified air stream may be equalto about 50% or less, equal to about 40% or less, equal to about 30% orless, or equal to about 20% or less of the initial formaldehyde contentin the unpurified air stream. The final ozone content of the purifiedair stream may be equal to about 50% or less, equal to about 40% orless, or equal to about 30% or less of the initial ozone content in theunpurified air stream. The final volatile organic compounds content ofthe purified air stream may be equal to about 90% or less, equal toabout 80% or less, or equal to about 70% or less of the initial volatileorganic compounds content in the unpurified air stream.

In some embodiments, the catalyst composition disposed within thehousing may be in an extrudate form as described in the catalystcomposition section above. In other embodiments, the catalystcomposition present within the housing may be disposed on a solidsubstrate, thereby forming a catalyst system disposed in a housing ofthe catalyst device. The catalyst system is described in more detail inthe catalyst composition section above.

In some embodiments, the catalyst device may be incorporated into aheating, ventilation, and air conditioning (HVAC) system. In someembodiments, the catalyst device may be a portable air purifier or anionic air purifier. In some embodiments, the catalyst device may beincorporated into a vehicle selected from the group consisting of motorvehicles, railed vehicles, watercraft, aircraft, and spacecraft. Forexample, the catalyst device may be incorporated into a cabin of anautomobile or an airplane. In some embodiments, the catalyst compositionmay remove gas phase contaminants from air streams in air purifierswhich use various purification technologies, such as filtration,ionization, washing and the like. For example, in ionic air purifiers,where gaseous contaminants are removed by ionization (plasma), thecatalyst composition may be used to remove ozone, or other pollutantsgenerated within the air cleaner, as well as pollutants present in theair outside the device.

In some embodiments, the present invention is directed to a method forpurifying an air flow stream. The method may comprise contacting anunpurified air flow stream with a catalyst composition to produce apurified air flow stream, wherein the unpurified air flow streamcontains a first formaldehyde content (or an initial formaldehydecontent), the purified air stream contains a second formaldehyde content(or a final formaldehyde content) that is less than the firstformaldehyde content, wherein the catalyst composition comprisesmanganese oxide, and wherein the catalyst composition comprises a BETsurface area ranging from about 5 m²/g to about 2000 m²/g, from about 10m²/g to about 2000 m²/g, from about 15 m²/g to about 2000 m²/g, fromabout 20 m²/g to about 2000 m²/g, from about 25 m²/g to about 2000 m²/g,from about 30 m²/g to about 2000 m²/g, from about 35 m²/g to about 2000m²/g, from about 40 m²/g to about 2000 m²/g, from about 45 m²/g to about2000 m²/g, from about 5 m²/g to about 1500 m²/g, from about 5 m²/g toabout 1300 m²/g, from about 5 m²/g to about 1100 m²/g, from about 5 m²/gto about 1000 m²/g, from about 5 m²/g to about 750 m²/g, from about 5m²/g to about 500 m²/g, from about 5 m²/g to about 400 m²/g, from about5 m²/g to about 300 m²/g, from about 5 m²/g to about 200 m²/g, fromabout 5 m²/g to about 150 m²/g, from about 5 m²/g to about 100 m²/g,from about 5 m²/g to about 75 m²/g, from about 5 m²/g to about 50 m²/g,from about 5 m²/g to about 30 m²/g, from about 50 m²/g to about 2000m²/g, from about 100 m²/g to about 2000 m²/g, from about 150 m²/g toabout 2000 m²/g, from about 170 m²/g to about 2000 m²/g, from about 50m²/g to about 1500 m²/g, from about 100 m²/g to about 1500 m²/g, fromabout 150 m²/g to about 1500 m²/g, from about 170 m²/g to about 1500m²/g, from about 50 m²/g to about 1300 m²/g, from about 100 m²/g toabout 1300 m²/g, from about 150 m²/g to about 1300 m²/g, from about 170m²/g to about 1300 m²/g, from about 50 m²/g to about 1100 m²/g, fromabout 100 m²/g to about 1100 m²/g, from about 150 m²/g to about 1100m²/g, from about 170 m²/g to about 1100 m²/g, from about 50 m²/g toabout 1000 m²/g, from about 100 m²/g to about 1000 m²/g, from about 150m²/g to about 1000 m²/g, from about 170 m²/g to about 1000 m²/g, fromabout 100 m²/g to about 500 m²/g, from about 100 m²/g to about 400 m²/g,from about 100 m²/g to about 350 m²/g, from about 100 m²/g to about 300m²/g, or from about 100 m²/g to about 250 m²/g, from about 150 m²/g toabout 500 m²/g, from about 150 m²/g to about 400 m²/g, from about 150m²/g to about 350 m²/g, from about 150 m²/g to about 300 m²/g, or fromabout 150 m²/g to about 250 m²/g. In some embodiments, the BET surfacearea ranges from about 70 m²/g to 150 m²/g, from about 70 m²/g to 125m²/g, from about 70 m²/g to 100 m²/g, from about 50 m²/g to 150 m²/g,from about 50 m²/g to 125 m²/g, from about 50 m²/g to 100 m²/g, fromabout 50 m²/g to 80 m²/g, from about 25 m²/g to 150 m²/g, from about 25m²/g to 125 m²/g, from about 25 m²/g to 100 m²/g, from about 25 m²/g to70 m²/g, from about 10 m²/g to 150 m²/g, from about 10 m²/g to 125 m²/g,from about 10 m²/g to 100 m²/g, from about 10 m²/g to 70 m²/g, fromabout 10 m²/g to 50 m²/g, from about 5 m²/g to 150 m²/g, from about 5m²/g to 125 m²/g, from about 5 m²/g to 100 m²/g, from about 5 m²/g to 70m²/g, from about 5 m²/g to 50 m²/g, from about 5 m²/g to 25 m²/g, orfrom about 5 m²/g to 10 m²/g. It is to be understood that the method forpurifying an air flow stream may be performed with any of the catalystcompositions disclosed herein.

In some embodiments, the method for purifying an air flow stream and thecatalyst composition utilized therein may produce a purified air streamat a first efficiency when first contacted with the unpurified air flowstream and may produce a purified air stream at a second efficiencyafter contacting the unpurified air flow stream for a certain duration,for example for three hours. In some embodiments, the second efficiencymay be reduced by about 20% or less, or by about 10% or less as comparedto the first efficiency.

In some embodiments, the contacting of the unpurified air stream withthe catalyst composition may occur at a temperature ranging from about10° C. to about 150° C., from about 15° C. to about 80° C., from about10° C. to about 50° C., or from about 20° C. to about 40° C., at about21° C., at about 25° C., or at about 35° C.; at a relative humidityranging from about 10% to about 90%; and at a space velocity rangingfrom about 100 h⁻¹ to about 1,000,000 h⁻¹.

Extruded Catalyst Composition Preparation

In some embodiments, the present invention is directed to a method forpreparing an extruded catalyst composition in accordance with process200 illustrated in FIG. 2 . The method may comprise mixing manganeseoxide in water to form an extrudable paste. In some embodiments, themethod may comprise forming an extrudable paste by mixing in watermanganese oxide and optionally one or more of an alkali metal, analkaline earth metal, zinc, iron, or combinations thereof, an inorganicoxide, a binder, and/or activated carbon, pursuant to blocks 202 and204. Additives such as pore builders and extrusion aids may further beadded to the paste. The order in which the components are presented inblock 202 is not to be construed as limiting and it is to be understoodthat unless otherwise noted, the components may be added at any order.The method may further comprise, pursuant to block 206, extruding thepaste to form an extruded catalyst composition of a desired shape andsize.

In some embodiments, the method may further optionally comprise dryingthe extruded catalyst composition particle(s), pursuant to block 208.The drying may occur at a temperature ranging from about 60° C. to about350° C., from about 80° C. to about 150° C., or at about 90° C. Thedrying may occur for a duration ranging from about 1 hour to about 24hours, from about 2 hours to about 12 hours, or for about 4 hours. Insome embodiments, the method may further optionally comprise calciningthe extruded catalyst composition particle(s), pursuant to block 210.The calcining may occur at a temperature ranging from about 90° C. toabout 1200° C., from about 100° C. to about 500° C., from about 100° C.to about 300° C., or at about 250° C. The calcining is optional and mayoccur for a duration of up to about 4 hours, from about 1.5 hours toabout 3 hours, or for about 2 hours.

It should be understood that the above steps of the flow diagrams ofFIG. 2 may be executed or performed in any order or sequence not limitedto the order and sequence shown and described. Also, some of the stepsin FIG. 2 may be executed or performed substantially simultaneously,where appropriate.

The final extruded catalyst composition may be porous and may have porevolumes ranging from about 0.3 mL/g to about 1.5 mL/g, from about 0.3mL/g to about 1 mL/g, from about 0.3 mL/g to about 0.9 mL/g, from about0.5 mL/g to about 0.9 mL/g, or from about 0.5 mL/g to about 0.75 mL/g.The final extruded catalyst composition may have a BET surface arearanging from about 10 m²/g to about 2000 m²/g, from about 15 m²/g toabout 2000 m²/g, from about 15 m²/g to about 1500 m²/g, from about 15m²/g to about 1300 m²/g, from about 15 m²/g to about 1100 m²/g, fromabout 15 m²/g to about 1000 m²/g, from about 15 m²/g to about 750 m²/g,from about 15 m²/g to about 500 m²/g, from about 15 m²/g to about 400m²/g, from about 15 m²/g to about 300 m²/g, from about 15 m²/g to about200 m²/g, from about 15 m²/g to about 150 m²/g, from about 15 m²/g toabout 100 m²/g, from about 15 m²/g to about 75 m²/g, from about 15 m²/gto about 50 m²/g, from about 15 m²/g to about 30 m²/g, from about 150m²/g to about 2000 m²/g, from about 170 m²/g to about 2000 m²/g, fromabout 150 m²/g to about 1500 m²/g, from about 170 m²/g to about 1500m²/g, from about 150 m²/g to about 1300 m²/g, from about 170 m²/g toabout 1300 m²/g, from about 150 m²/g to about 1100 m²/g, from about 170m²/g to about 1100 m²/g, from about 150 m²/g to about 1000 m²/g, fromabout 170 m²/g to about 1000 m²/g, from about 150 m²/g to about 500m²/g, from about 170 m²/g to about 400 m²/g, from about 150 m²/g toabout 350 m²/g, from about 175 m²/g to about 300 m²/g, or from about 200m²/g to about 250 m²/g. In some embodiments, the BET surface area isfrom about 70 m²/g to 150 m²/g. In some embodiments, the resultingextruded catalyst composition is configured to remove formaldehyde at afirst efficiency when first introduced to an unpurified air flow streamand at a second efficiency after contacting the unpurified air streamfor a period of time, such as three hours. In some embodiments, thesecond efficiency is reduced by about 20% or less or by about 10% orless as compared to the first efficiency.

In some embodiments, the order of addition of the various components tothe mixture with water to form the extrudable paste is inconsequential.In other embodiments, the one or more of alkali metal, alkaline earthmetal, zinc, iron, or combinations thereof may be added last to theextrudable paste to achieve improved contaminants conversion efficiency.Improved contaminants conversion efficiency may be determined based onthe first efficiency illustrating how effectively contaminants areconverted or removed from the unpurified air stream during the initialcontact between the unpurified air stream and the catalyst composition.Improved contaminants conversion efficiency is also evident when thedifference between the first and the second conversion efficiencies isminimal.

Coating Layer Catalyst Composition Preparation

In some embodiments, the invention is directed to a method for preparinga catalyst composition disposed onto a substrate as a coating layer oras a plurality of coating layers. The method 300 is illustrated in FIG.3 . In some embodiments, the method may comprise dispersing in watermanganese oxide and optionally one or more of an alkali metal, analkaline earth metal, zinc, iron, or combinations thereof, an inorganicoxide, a binder, and/or activated carbon, pursuant to block 302. In someembodiments, the method may comprise adding a pH adjusting agent such asacetic acid or a cellulose based thickener. In some embodiments, themethod may further comprise adding a dispersant such as Dispex N40V,Solsphere 2700, Carbosphere and the like. In some embodiments, themethod may further comprise coating the catalyst composition slurry ontoa substrate, pursuant to block 304. The slurry may be, for example,sprayed onto the solid substrate, dip-coated onto the solid substrate,or directly deposited onto the solid substrate.

In some embodiments, the method may optionally further comprise dryingthe coated substrate, pursuant to block 306. The drying may occur at atemperature ranging from about 60° C. to about 150° C., from about 80°C. to about 130° C., or at about 90° C. The drying may occur for aduration ranging from about 2 minutes to about 8 hours, from about 1hour to about 8 hours, from about 2 hours to about 6 hours, or for about2 hours. In some embodiments, the method may optionally further comprisecalcining the extruded catalyst composition particle(s), pursuant toblock 308. The calcining may occur at a temperature ranging from about70° C. to about 1200° C., from about 80° C. to about 800° C., from about100° C. to about 600° C., from about 120° C. to about 300° C., or atabout 250° C. The calcining is optional and may occur for a duration ofup to about 4 hours, from about 0.5 hours to about 3 hours, or for about1 hour.

The catalyst composition may be coated onto the substrate repeatedlyuntil a desired weight gain is achieved. In some embodiments, thedesired weight gain may range from about 0.5 g/in³ to about 10 g/in³,from about 0.5 g/in³ to about 5 g/in³, from about 0.5 g/in³ to about 4g/in³, about 1 g/in³, or about 2 g/in³.

It should be understood that the steps in FIG. 3 may be executed orperformed in any order or sequence not limited to the order and sequenceshown and described. Also, some of the steps in FIG. 3 may be executedor performed substantially simultaneously, where appropriate.

The final catalyst system comprising a catalyst composition layerdeposited onto a substrate may be porous and may have pore volumesranging from about 0.3 mL/g to about 1.5 mL/g, from about 0.3 mL/g toabout 1 mL/g, from about 0.3 mL/g to about 0.9 mL/g, from about 0.5 mL/gto about 0.9 mL/g, or from about 0.5 mL/g to about 0.75 mL/g. The finalcatalyst system comprising a catalyst composition layer deposited onto asubstrate may have a BET surface area ranging from about 5 m²/g to about2000 m²/g, from about 10 m²/g to about 2000 m²/g, from about 15 m²/g toabout 2000 m²/g, from about 20 m²/g to about 2000 m²/g, from about 25m²/g to about 2000 m²/g, from about 30 m²/g to about 2000 m²/g, fromabout 35 m²/g to about 2000 m²/g, from about 40 m²/g to about 2000 m²/g,from about 45 m²/g to about 2000 m²/g, from about 5 m²/g to about 1500m²/g, from about 5 m²/g to about 1300 m²/g, from about 5 m²/g to about1100 m²/g, from about 5 m²/g to about 1000 m²/g, from about 5 m²/g toabout 750 m²/g, from about 5 m²/g to about 500 m²/g, from about 5 m²/gto about 400 m²/g, from about 5 m²/g to about 300 m²/g, from about 5m²/g to about 200 m²/g, from about 5 m²/g to about 150 m²/g, from about5 m²/g to about 100 m²/g, from about 5 m²/g to about 75 m²/g, from about5 m²/g to about 50 m²/g, from about 5 m²/g to about 30 m²/g, from about50 m²/g to about 2000 m²/g, from about 100 m²/g to about 2000 m²/g, fromabout 150 m²/g to about 2000 m²/g, from about 170 m²/g to about 2000m²/g, from about 50 m²/g to about 1500 m²/g, from about 100 m²/g toabout 1500 m²/g, from about 150 m²/g to about 1500 m²/g, from about 170m²/g to about 1500 m²/g, from about 50 m²/g to about 1300 m²/g, fromabout 100 m²/g to about 1300 m²/g, from about 150 m²/g to about 1300m²/g, from about 170 m²/g to about 1300 m²/g, from about 50 m²/g toabout 1100 m²/g, from about 100 m²/g to about 1100 m²/g, from about 150m²/g to about 1100 m²/g, from about 170 m²/g to about 1100 m²/g, fromabout 50 m²/g to about 1000 m²/g, from about 100 m²/g to about 1000m²/g, from about 150 m²/g to about 1000 m²/g, from about 170 m²/g toabout 1000 m²/g, from about 100 m²/g to about 500 m²/g, from about 100m²/g to about 400 m²/g, from about 100 m²/g to about 350 m²/g, fromabout 100 m²/g to about 300 m²/g, or from about 100 m²/g to about 250m²/g, from about 150 m²/g to about 500 m²/g, from about 150 m²/g toabout 400 m²/g, from about 150 m²/g to about 350 m²/g, from about 150m²/g to about 300 m²/g, or from about 150 m²/g to about 250 m²/g. Insome embodiments, the BET surface area ranges from about 70 m²/g to 150m²/g, from about 70 m²/g to 125 m²/g, from about 70 m²/g to 100 m²/g,from about 50 m²/g to 150 m²/g, from about 50 m²/g to 125 m²/g, fromabout 50 m²/g to 100 m²/g, from about 50 m²/g to 80 m²/g, from about 25m²/g to 150 m²/g, from about 25 m²/g to 125 m²/g, from about 25 m²/g to100 m²/g, from about 25 m²/g to 70 m²/g, from about 10 m²/g to 150 m²/g,from about 10 m²/g to 125 m²/g, from about 10 m²/g to 100 m²/g, fromabout 10 m²/g to 70 m²/g, from about 10 m²/g to 50 m²/g, from about 5m²/g to 150 m²/g, from about 5 m²/g to 125 m²/g, from about 5 m²/g to100 m²/g, from about 5 m²/g to 70 m²/g, from about 5 m²/g to 50 m²/g,from about 5 m²/g to 25 m²/g, or from about 5 m²/g to 10 m²/g.

FIGS. 4, 5 and 6 described in detail below are depictions of theone-pass test and system test set by the National Standards of thePeople's Republic of China and jointly issued by the GeneralAdministration of Quality Supervision, Inspection and Quarantine and theStandardization Administration of the People's Republic of China, alsoreferred to as GB/T 18801 guidelines.

FIG. 4 depicts a schematic diagram for air purification in accordancewith an embodiment. This schematic diagram illustrates a one-pass testset up configured to allow for quick sample screening and acceleratedtesting of the catalyst composition's efficacy.

The testing device comprises an air duct system 400, a pollutantgenerator 404, a mixing valve 420, an upstream sampling tube 408, adownstream sampling tube 416, and an air cleaner 414. In the one-passtest ambient air 402 enters mixing valve 420 where it is mixed withpollutants (such as formaldehyde and VOCs) generated in pollutantgenerator 404. Resulting polluted air 406 exits mixing valve 420 andenters air duct system 400 where the efficacy of air cleaner 414 istested.

Air duct system 400 may be bent or folded. In some embodiments, if airduct system 400 is bent, a straight duct segment of at least three timesthe duct diameter is laid before and after the bend to ensure stable airflow. A sample of polluted air 406 entering first air duct segment 410of the air duct may be sampled through upstream sampling tube 408 todetermine the starting pollutant concentration in the unpurified airstream. Sampling tube 408 may comprise stainless steel or Teflon, andhave smooth inner walls.

After passing first air duct segment 410, unpurified polluted air 406contacts air cleaner 414. Air cleaner 414 includes a catalystcomposition, either present as extruded catalyst particle(s) or as acatalyst layer(s) disposed on a substrate, wherein the catalystcomposition may be any of the catalyst compositions disclosed herein.

Once unpurified polluted air 406 contacts air cleaner 414, purified airenters the second air duct segment 412. Second air duct segment mayoptionally include an air volume measuring device 422. Air volumemeasuring device 422 may include a standard orifice plate, a standardnozzle and other throttling devices connected to a micromanometer. Theresulting pollutant concentration in purified air flow present in thesecond air duct segment 412 may be tested through downstream samplingtube 416. Sampling tube 416 may comprise stainless steel or Teflon, andhave smooth inner walls. Resulting purified air 424 exits air ductsystem 400 and is collected for formaldehyde conversion testing and/orany other contaminants or pollutants conversion testing.

FIG. 5 depicts a schematic diagram for air purification in accordancewith an embodiment of the invention. This schematic illustrates a systemtest set up configured according to national standard and critical forproduct performance evaluation.

The system test set up comprises a test chamber 500, a central platform504, a catalyst device 508 to be tested, unpurified air inlet 506, fan510 to allow for air circulation, and a unit 502 controlling temperatureand humidity.

Unpurified air flow enters chamber 500 through unpurified air inlet 506.The unpurified air stream is drawn into air eddy formed by aircirculation resulting from the operation of fan 510. Once the initialpollutant concentration in chamber 500 reaches a predetermined initialvalue, unpurified air inlet 506 is closed. Fan 510 may continue tooperate for a period of time to ensure even distribution of thepollutant in chamber 500. Once even distribution of the pollutant isachieved, fan 510 is turned off. The point at which the fan is turnedoff is t=0 and the concentration is recorded as C₀. For example, thetargeted initial concentration of formaldehyde may be about 1.00±0.2mg/m³. Immediately thereafter the testing begins. Samples are collectedevery five minutes for a period of an hour to evaluate the cleaningcapacity of the catalyst device in terms of Clean Air Delivery Rate(CADR) for gaseous pollutants such as formaldehyde.

The CADR is calculated based on Formula I:CADR=60·(k _(e) −k _(n))·V  Formula Iwherein k_(e) represents the total decay constant, k_(n) representsnatural decay constant, V represents the test chamber volume in m³, and(k_(e)−k_(n)) is calculated based on Formula II:(k _(e) −k _(n))·t=−ln(C _(t) /C ₀)  Formula IIwherein t represent the total testing time, C_(t) represents theconcentration at time t in mg/m³, and C₀ represents the concentration attime t=0 in mg/m³.

FIG. 6 depicts an illustrative control process for air purification inaccordance with an embodiment of the invention. The control process maybe applied to a similar system test chamber as illustrated in theschematic of FIG. 5 . The method described by this control process isused to test the half life time of a catalyst device according to anembodiment of the invention. “Half life time of a catalyst device”refers to the number of days or hours after which the catalyst devicehas a CADR that is 50% lower than the initial CADR value produced by thecatalyst device at the start of the catalyst device's operation.

According to FIG. 6 the testing begins by obtaining the CADR valueproduced by the catalyst device at the start of the catalyst device'soperation (t=0), also known as CADR₀. Subsequently, the catalyst deviceis optionally subjected to an Acceleration Test. An “Acceleration Test”refers to extreme condition that may impact or deteriorate the efficacyof the catalyst device more rapidly, such as higher pollutantconcentration or continuous generation of pollutants. The AccelerationTest results will then allow to estimate the catalyst device's life spanunder real life conditions.

After the catalyst device is aged for eight hours another sample istaken to obtain the CADR value at t=n, also known as CADR_(n). IfCADR_(n) value is greater than 50 percent of the CADR₀ value, thecatalyst device is considered as still operable and the testingcontinues by repeating the optional acceleration test, aging thecatalyst device, and measuring the CADR_(n) value after each subsequentcycle. Once the CADR_(n) value is lower or equal to 50 percent of theCADR₀ value, the life span of the catalyst device is deemed to haveended and the overall Cumulate Clean Mass (CCM) generated by thecatalyst device is calculated.

In some embodiments, any of the catalyst compositions described hereinmay be incorporated into polytetrafluoroethylene (PTFE) sheets (e.g.,fibrillated PTFE sheets), for example, as cross-flow filters forformaldehyde/VOC removal. Such embodiments may be incorporated into abuilding HVAC system, an indoor air purifier, a filter for a gas mask,an air filter or off-gas treatment for an industrial plant, a pollutantremoval system for drinking water, an odor removal system for cabin air(e.g., for automobiles or aircraft) or building ventilation, a humiditycontrol system, a clean room air filtration system, or systems forenvironmental pollutant removal. In some embodiments, prior toincorporation into a PTFE sheet, the catalyst composition or adsorbentpowder thereof may be processed into a three dimensional structurecharacterized by low pressure drop (due to defined flow channels), highaccessibility of active sites (due to the use of a porous fibrillatingbinder), and high volumetric capacity (due to low binder content and alack of inert support structure.

ILLUSTRATIVE EXAMPLES

The following examples are set forth to assist in understanding theembodiments described herein and should not be construed as specificallylimiting the embodiments described and claimed herein. Such variations,including the substitution of all equivalents now known or laterdeveloped, which would be within the purview of those skilled in theart, and changes in formulation or minor changes in experimental design,are to be considered to fall within the scope of the embodimentsincorporated herein.

Example 1: Extrudate Preparation 1

70 grams (g) of manganese oxide polymorph I powder and 30 g of Versal250 and water were thoroughly hand mixed to form an extrudable paste.1/16″ extrudates were pressed using a Carver press containing a 1.6 mmhole at the bottom. The solids were dried at 90° C. for 2 hours andcalcined for 2 hours at 250° C.

Example 2: Extrudate Preparation 2

42 g of manganese oxide polymorph I powder, 42 g of Ceria powder, 16 gof Versal 250 and water were thoroughly hand mixed to form an extrudablepaste. 1/16″ extrudates were pressed using a Carver press containing a1.6 mm hole at the bottom. The solid were dried at 90° C. for 2 hoursand calcined for 2 hours at 250° C.

Example 3: Extrudate Preparation 3

39 g of manganese oxide polymorph I powder, 39 g of Ceria powder, 7 g ofsodium nitrate, 16 g of Versal 250 and water were thoroughly hand mixedto form an extrudable paste. 1/16″ extrudates were pressed using aCarver press containing a 1.6 mm hole at the bottom. The solid weredried at 90° C. for 2 hours and calcined for 2 hours at 250° C.

Example 4: Extrudate Preparation 4

50 g of manganese oxide polymorph I powder and 50 g of Versal 250 andwater were thoroughly hand mixed to form an extrudable paste. 1/16″extrudates were pressed using a Carver press containing a 1.6 mm hole atthe bottom. The solid were dried at 90° C. for 2 hours and calcined for2 hours at 250° C.

Example 5: Extrudate Preparation 50% Manganese Oxide Polymorph I/50%Sipernat Silica

50 g of manganese oxide polymorph I powder and 50 g of SipernatSilicaand water were thoroughly hand mixed to form an extrudable paste. 1/16″extrudates were pressed using a Carver press containing a 1.6 mm hole atthe bottom. The solid were dried at 90° C. for 2 hours and calcined for2 hours at 250° C.

Example 6: Extrudate Preparation 50% Manganese Oxide Polymorph I/50%Bentonite

50 g of manganese oxide polymorph I powder and 50 g of Bentonite andwater were thoroughly hand mixed to form an extrudable paste. 1/16″extrudates were pressed using a Carver press containing a 1.6 mm hole atthe bottom. The solid were dried at 90° C. for 2 hours and calcined for2 hours at 250° C.

Example 7: Extrudate Preparation 50% Manganese Oxide Polymorph I/50%VersalB

50 g of manganese oxide polymorph I powder and 50 g of Versal B andwater were thoroughly hand mixed to form an extrudable paste. 1/16″extrudates were pressed using a Carver press containing a 1.6 mm hole atthe bottom. The solid were dried at 90° C. for 2 hours and calcined for2 hours at 250° C.

Example 8: Extrudate Preparation 50% Manganese Oxide Polymorph I/50%ZrO₂

50 g of manganese oxide polymorph I powder and 50 g of zirconia andwater were thoroughly hand mixed to form an extrudable paste. 1/16″extrudates were pressed using a Carver press containing a 1.6 mm hole atthe bottom. The solid were dried at 90° C. for 2 hours and calcined for2 hours at 250° C.

Example 9: Extrudate Preparation 50% Manganese Oxide Polymorph I/15%CeO₂/5% Bentonite/2% Na/1%9 Cellulose/27% Versal V-250

80.1 g of manganese oxide polymorph I powder, 23 g of ceria powder, 10.9g of sodium bicarbonate, 42.8 g of Versal V-250, 8.3 g bentonite(approximate composition: 61 wt % SiO₂, 21 wt % Al₂O₃, 5 wt % Fe₂O₃, 4.6wt % CaO, 4 wt % MgO based on total Bentonite weight), 2.3 g carbonylcellulose and water were thoroughly hand mixed to form an extrudablepaste. 1/16″ extrudates were pressed using a Carver press containing a1.6 mm hole at the bottom. The solid were dried at 90° C. for 2 hoursand calcined for 2 hours at 250° C.

Example 10: Extrudate Preparation 35% Manganese Oxide Polymorph I/35%CeO₂/30% Versal V-250

35 g of manganese oxide polymorph I powder, 35 g of ceria powder, 30 gof Versal V-250 and water were thoroughly hand mixed to form anextrudable paste. 1/16″ extrudates were pressed using a Carver presscontaining a 1.6 mm hole at the bottom. The solid were dried at 90° C.for 2 hours and calcined for 2 hours at 250° C.

Example 11: Extrudate Preparation 50% Poorly CrystallineCryptomelane/50% Versal V-250

50 g of poorly crystalline cryptomelane powder and 50 g of Versal V-250and water were thoroughly hand mixed to form an extrudable paste. 1/16″extrudates were pressed using a Carver press containing a 1.6 mm hole atthe bottom. The solid were dried at 90° C. for 2 hours and calcined for2 hours at 250° C.

Example 12: 50% Extrudates from Example 9/50% Activated Carbon

10 mL of Example 9 extrudates were physically mixed with 10 mL ofactivated carbon.

Example 13: 75% Extrudates from Example 9/25% Activated Carbon

15 mL of Example 9 extrudates were physically mixed with 5 mL ofactivated carbon.

A packed bed column was used to evaluate the performance of theExamples, and is illustrated in FIG. 7 . Results for the catalystcompositions prepared according to examples 1-13 after three hours ofoperation in the reactor are shown in FIG. 8 . The packed bed was 1.5″(diameter)×0.69″ (height). The operation conditions were: an unpurifiedair flow stream (16.9 1/min) having about 2 ppm formaldehyde, 20%relative humidity in air at 30° C. was directed through the catalystbed. For examples 9, 12, 13 and activated carbon, 20 ppm toluene wasadded to the unpurified air flow. The conversion values depicted in FIG.8 are initial and after 3 hours.

Example 14: Cryptomelane

73.4 g of ceria and 73.4 g of cryptomelane manganese oxide weredispersed in 191 g of water, and a solution of 4.8 g alumina sol and 4.8g acetic acid in 16.8 g water was added to the resulting slurry. Asolution of cellulose base thickener (0.2 g) was added to the slurrywith vigorous mixing. This slurry was used to coat ceramic monolithicsubstrates (cordierite; 400 cells per square inch). Afterwards thecoated monolith was dried at 120° C. for 2 hours and calcined at 250° C.for 1 hour. The coating was repeated until the weight gain of themonolithic substrate was 1 g/in³.

Example 15: Manganese Oxide Polymorph I

73.4 g of ceria and 73.4 g of manganese oxide polymorph I were dispersedin 191 g of water, and a solution of 4.8 g alumina sol and 4.8 g aceticacid in 16.8 g water was added to the resulting slurry. A solution ofcellulose base thickener (0.2 g) was added to the slurry with vigorousmixing. This slurry was used to coat ceramic monolithic substrates(cordierite; 400 cells per square inch). Afterwards the coated monolithwas dried at 120° C. for 2 hours and calcined at 250° C. for 1 hour. Thecoating was repeated until the weight gain of the monolithic substratewas 1 g/in³ or 2 g/in³. The resulting surface area of the catalystcomposition was 157 m²/g.

Example 16: Poorly Crystalline Cryptomelane

73.4 g of ceria and 73.4 g of poorly crystalline cryptomelane weredispersed in 191 g of water, and a solution of 4.8 g alumina sol and 4.8g acetic acid in 16.8 g water was added to the resulting slurry. Asolution of cellulose base thickener (0.2 g) was added to the slurrywith vigorous mixing. This slurry was used to coat ceramic monolithicsubstrates (cordierite; 400 cells per square inch). Afterwards thecoated monolith was dried at 120° C. for 2 hours and calcined at 250° C.for 1 hour. The coating was repeated until the weight gain of themonolithic substrate was 1 g/in³. The resulting surface area of thecalcined catalyst composition was 166 m²/g.

FIG. 9 shows a formaldehyde conversion comparison of catalystcompositions prepared according to examples 14-16. The coated cordierite(400 cpsi) was 1.7″ (height) and 1″ (diameter) coated with 1 g/in³catalyst. The operation conditions were: an unpurified air flow stream(36.5 L/min) having about 2 ppm formaldehyde, 20% relative humidity inair at 30° C. was directed over the catalyst. The conversion valuesdepicted in FIG. 9 are initial and after 3 hours.

Example 17: 80% Manganese Oxide Polymorph I/20% Activated Carbon

18.5 g activated carbon and 49.7 g manganese oxide polymorph I weredispersed in 165.7 g of water, and a solution of 2.09 g alumina sol and1.2 g acetic acid in 10 g water was added to the resulting slurry. 3.5 gof sodium carbonate was added to the slurry while stirring. This slurrywas used to coat aluminum substrates (250 cells per square inch), 0.69″(height) and 1.5″ (diameter) coated to 1 g/in³ catalyst. The operationconditions were: an unpurified air flow stream (38 L/min) having about 2ppm formaldehyde, 20 ppm toluene, 20% relative humidity in air at 30° C.The initial formaldehyde conversion was 80%, and 17% after 3 hours. Thetoluene absorption was 45% initially, and 2% after 3 hours.

Example 18

40 g of ceria and 172 g of manganese oxide polymorph I were dispersed in203 g of water, and a solution of 10 g alumina sol and 2 g acetic acidin 30 g water was added to the resulting slurry. 0.4 g of a dispersantas added. This slurry was used to coat aluminum substrates (250 cellsper square inch), 1″ (height) and 1.5″ (diameter) coated to 1.1 g/in³catalyst. The coated monolith was dried at 90° C. for 2 hours andcalcined at 140° C. for 2 hours. The testing conditions were: anunpurified air flow stream (36 L/min) having about 2 ppm formaldehyde,20% relative humidity in air at 30° C. was directed over the catalyst.The initial formaldehyde conversion was 97%, and 37% after 3 hours.

Example 19

77.8 g of ceria, 21.5 g sodium carbonate (0.002% NaCl impurity), and 328g of manganese oxide polymorph I were dispersed in 550 g of water, and asolution of 13 g alumina sol and 9.6 g acetic acid in 50 g water wasadded to the resulting slurry. 0.8 g of a dispersant was added. Thisslurry was used to coat aluminum substrates (250 cells per square inch),0.75″ (height) and 1.5″ (diameter) coated to 1.1 g/in³ catalyst. Thecoated monolith is dried at 90° C. for 2 hours and calcined at 140° C.for 2 hour. The testing conditions were: an unpurified air flow stream(36 L/min) having about 2 ppm formaldehyde, 20% relative humidity in airat 30° C. was directed over the catalyst. The initial formaldehydeconversion was 94%, and 70% after 2 hours.

Example 20: Catalyst with Polytetrafluoroethylene (PTFE) Binder

0.25 g of dispersant was dissolved in 170 g of water. While mixing, 24.3g of ceria was added to the stirred solution, followed by 104 g ofmanganese oxide polymorph I and 6.7 g of sodium carbonate monoxide salt.4.5 g of PTFE binder (60% wt dispersion in water) was added to theslurry with vigorous mixing followed by adding 16.5 g of a solution ofcarbohydrate based thickener. This slurry was used to coat aluminumsubstrates (250 cells per square inch), 0.8″ (height) and 1.5″(diameter) coated to 1.4 g/in³ catalyst. The coated monolith was driedat 90° C. for several hours. The testing conditions were: an unpurifiedair flow stream (38 L/min) having about 2 ppm formaldehyde, 20% relativehumidity in air at 30° C. was directed over the catalyst. The initialformaldehyde conversion was 90%, and 58% after 3 hours.

Example 21: Catalyst with PTFE Binder

1 g of dispersant was dissolved in 315 g of water. While mixing, 253 gof manganese oxide polymorph I was added to the stirred solutionfollowed by 27.45 g of potassium hydroxide. The pH of the solution wasadjusted to 9 with ammonium hydroxide prior to adding 33.1 g of PTFEbinder (60% wt dispersion in water) to the slurry with vigorous mixing.Then a solution of 32.6 g of carbohydrate based thickener was added tothe vigorously mixed slurry. This slurry was used to coat aluminumsubstrates (250 cells per square inch), 0.8″ (height) and 1.5″(diameter) coated to 1.7 g/in³ catalyst. The coated monolith was driedat 90° C. for several hours. The testing conditions were: an unpurifiedair flow stream (38 1/min) having about 2 ppm formaldehyde, 20% relativehumidity in air at 30° C. was directed over the catalyst. The initialformaldehyde conversion was 95%, and 58% after 3 hours.

Example 22: Catalyst with Styrene-Acrylic Binder

1 g of dispersant was dissolved in 229 g of water. While stirring, 46 gof ceria was added to the resulting solution followed by 198 g ofmanganese oxide polymorph I. While mixing well, 35 g of sodium hydroxidewas added. 25.1 g of styrene-acrylic binder (50% wt. dispersion inwater) was added to the slurry with vigorous mixing. This slurry wasused to coat aluminum substrates (250 cells per square inch), 0.8″(height) and 1.5″ (diameter) coated to 1.3 g/in³ catalyst. The coatedmonolith was dried between 110° C. and 140° C. for several hours. Thetesting conditions were: an unpurified air flow stream (38 1/min) havingabout 2 ppm formaldehyde, 20% relative humidity in air at 30° C. wasdirected over the catalyst. The initial formaldehyde conversion was 96%,and 58% after 3 hours.

Example 23: Catalyst with Styrene-Acrylic Binder

0.24 g of carbohydrate based thickener was dispersed in 16.9 g of waterfollowed dispersing 0.24 g of surfactant in 121.2 g of water in anothercontainer, followed by adding the pre-prepared thickener solution. Whilestirring, 101.9 g of manganese oxide polymorph I was added to theresulting solution followed by 8.4 g of sodium hydroxide. 36.0 g ofstyrene acrylic binder (50% wt dispersion in water) was added to theslurry with vigorous mixing followed by adding 7.9 g of rinse water.This slurry was used to coat aluminum honeycomb and PU foam substrates0.8″ (height) and 1.5″ (diameter) coated to 1 g/in³ catalyst. The coatedsubstrate was dried at 90° C. for several hours. The testing conditionsfor coated aluminum were: an unpurified air flow stream (38 1/min)having about 2 ppm formaldehyde, 20% relative humidity in air at 30° C.was directed over the catalyst. The initial formaldehyde conversion was70%, and 38% after 3 hours.

Example 24: Catalyst with No Chloride or Sulfate Impurities

1 g of dispersant was dissolved in 255 g of water followed by 39.6 gpotassium carbonate salt. 230 g of manganese oxide polymorph I wereadded to the slurry. 30 g of a styrene acrylic binder was then added tothe slurry followed by ammonium hydroxide to adjust the pH to 9. Thisslurry was used to coat aluminum monolithic substrates (225 cpsi).Afterwards the coated monolith was dried at 90° C. for 2 hours. Thecoating was repeated until the weight gain of the monolithic substratewas 2 g/in³.

Example 25 Catalyst with 0.25% Potassium Chloride Impurity

1 g of dispersant was dissolved in 255 g of water followed by 39.6 gpotassium carbonate salt (0.25% potassium chloride impurity). 230 g ofmanganese oxide polymorph I were added to the slurry. 30 g of a styreneacrylic binder was then added to the slurry followed by ammoniumhydroxide to adjust the pH to 9. This slurry was used to coat aluminummonolithic substrates (225 cpsi). Afterwards the coated monolith wasdried at 90° C. for 2 hours. The coating was repeated until the weightgain of the monolithic substrate was 2 g/in³.

Example 26: Catalyst with 0.5% Potassium Chloride Impurity

1 g of dispersant was dissolved in 255 g of water followed by 39.6 gpotassium carbonate salt (0.5% potassium chloride impurity). 230 g ofmanganese oxide plymorph I were added to the slurry. 30 g of a styreneacrylic binder was then added to the slurry followed by ammoniumhydroxide to adjust the pH to 9. This slurry was used to coat aluminummonolithic substrates (225 cpsi). Afterwards the coated monolith wasdried at 90° C. for 2 hours. The coating was repeated until the weightgain of the monolithic substrate was 2 g/in³.

Example 27: Catalyst with 0.5% Potassium Sulfate Impurity

1 g of dispersant was dissolved in 255 g of water followed by 39.6 gpotassium carbonate salt (0.5% potassium sulfate). 230 g of manganeseoxide polymorph I were added to the slurry. 30 g of a styrene acrylicbinder was then added to the slurry followed by ammonium hydroxide toadjust the pH to 9. This slurry was used to coat aluminum monolithicsubstrates (225 cpsi). Afterwards the coated monolith was dried at 90°C. for 2 hours. The coating was repeated until the weight gain of themonolithic substrate was 2 g/in³.

FIG. 10 shows a formaldehyde conversion comparison of catalystcompositions prepared according to examples 24-27. The coated aluminum(250 cpsi) was 1.6″ (height) and 1″ (diameter) coated with 2 g/in³catalyst. The operation conditions were: an unpurified air flow stream(34 L/min) having about 5 ppm formaldehyde, 20% relative humidity in airat 30° C. The conversion values depicted in FIG. 10 are initial andafter 3 hours.

Example 28: Preparation of Catalyst Filter Sheet

92.5 g of potassium modified MnOx powder and 7.5 g of PTFE powder weredosed into a cylindrical 1 liter. The container was placed on a rollmixer for 1 hour at 60 rpm. Subsequently, 1.5 kg of 8 mm steel ballswere added and the container was again placed on the roll mixer for 5min. The material was removed from the container and the steel ballswere separated using a 5 mm mesh stainless steel wire sieve. Thematerial was then dosed onto a linear conveyor belt. The material wascalendered into a film by 6 brass rolls with a diameter of 60 mm and alinear force of 1.2 kN/m. The resulting film was cut into sheets of 5×25cm. Two sheets were placed on top of each other manually and laminatedtogether by compressing the sheet to a thickness of 1 mm using a 60 mmdiameter brass cylinder and 1 mm PTFE ships for thickness control. Thisstep was repeated 10 times.

The resulting free standing film had a density of 1.08 g/cm³ and athickness of 1 mm and was cut to a width of 25 mm and 200 mm length.Three of these sheets were corrugated using a flat brass matrix at apressure of ˜1 MPa.

The corrugated sheet was positioned on top of flat sheet and this stackwas rolled up manually to fit into a cylindrical sample holder with aninner diameter of 34 mm and a length of 20 mm. The total mass of thecatalyst film was 12.6 g. The testing conditions for the filter: anunpurified air flow stream (33 1/min) having about 2 ppm formaldehyde,20% relative humidity in air at 30° C. The initial formaldehydeconversion was 70%, and 55% after 3 hours.

Example 28: Catalyst for Ozone Testing

1 g of dispersant was dissolved in 213 g of water followed by 31 gpotassium carbonate salt and 16.3 g of a 45% potassium hydroxidesolution. 230 g of manganese oxide polymorph I was added to the slurryfollowed by 30 g of a styrene acrylic binder. This slurry was used tocoat aluminum monolithic substrates (225 cpsi). Afterwards the coatedmonolith was dried at 90° C. for 2 hours. The coating was repeated untilthe weight gain of the monolithic substrate was 2 g/in³

Testing of Catalyst for Ozone Conversion

The catalysts of examples 15 (2 g/in³ loading) and 29 were fitted in thetube of a plug flow reactor and operated with a feed gas containing thespecified concentration of ozone in air at a dew point of 15° C. ateither 30° C. or 75° C. gas temperature. The ozone concentration wasmeasured with an UV photometric analyzer (Tanabyte model 722, US EPAEquivalent Method EQOA-0407-165). The gas flow rate (at roomtemperature) was set to achieve space velocities of 200,000-800,000 h⁻¹.The results are listed in Table 2. High ozone conversion was achieved,even at low temperature and high flow rates.

TABLE 2 Ozone conversion performance Example 15 Example 15 (2 g/in³)Example 28 (2 g/in³) Space velocity Conversion at Conversion atConversion at 800 [×10³ h⁻¹] 250 ppb O₃ 250 ppb O₃ ppb O₃ T = 75° C. 20087.4% 84.2% 87.9% 400 69.4% 64.9% 69.7% 600 58.4% 53.9% 58.3% 800 54.1%47.6% 51.6% T = 30° C. 200 80.6% 76.6% 77.1% 400 61.8% 56.0% 57.6% 60049.6% 41.7% 47.0% 800 43.7% 37.4% 40.4%

The use of the terms “a,” “an,” “the,” and similar referents in thecontext of describing the materials and methods discussed herein(especially in the context of the following claims) are to be construedto cover both the singular and the plural, unless otherwise indicatedherein or clearly contradicted by context. Recitation of ranges ofvalues herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to betterilluminate the materials and methods and does not pose a limitation onthe scope unless otherwise claimed. No language in the specificationshould be construed as indicating any non-claimed element as essentialto the practice of the disclosed materials and methods.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe present disclosure. Thus, the appearances of the phrases such as “inone or more embodiments,” “in certain embodiments,” “in one embodiment,”or “in an embodiment” in various places throughout this specificationare not necessarily referring to the same embodiment of the presentdisclosure. Furthermore, the particular features, structures, materials,or characteristics may be combined in any suitable manner in one or moreembodiments.

Although the embodiments disclosed herein have been described withreference to particular embodiments it is to be understood that theseembodiments are merely illustrative of the principles and applicationsof the present disclosure. It will be apparent to those skilled in theart that various modifications and variations can be made to the methodand apparatus of the present disclosure without departing from thespirit and scope of the disclosure. Thus, it is intended that thepresent disclosure include modifications and variations that are withinthe scope of the appended claims and their equivalents, and theabove-described embodiments are presented for purposes of illustrationand not of limitation.

What is claimed is:
 1. A catalyst composition comprising: manganeseoxide; bentonite from about 40 wt % to about 50 wt % based on a totalweight of the catalyst composition; and a polymer binder comprisingpoly(tetrafluoroethylene), acrylic/styrene acrylic copolymer latex, or acombination thereof, wherein the catalyst composition is disposed on asubstrate selected from a polymer substrate, a foam substrate, a papersubstrate, a nonwoven filter, a paper filter, a fibrous filter, or acombination thereof, and wherein the catalyst composition is adapted toremove one or more of formaldehyde, ozone, carbon monoxide, nitrogenoxide, amines, sulfur compounds, thiols, chlorinated hydrocarbons, orvolatile organic compounds from an unpurified air supply, and wherein aBJH pore volume of the catalyst composition ranges from about 0.3 mL/gto about 1.5 mL/g.
 2. The catalyst composition of claim 1, wherein thepolymer binder further comprises a polymer selected from a groupconsisting of polyethylene, polypropylene, polyolefin copolymers,polyisoprene, polybutadiene, polybutadiene copolymers, chlorinatedrubber, nitrile rubber, polychloroprene, ethylene-propylene-dieneelastomers, polystyrene, polyacrylate, polymethacrylate,polyacrylonitrile, poly(vinyl esters), poly(vinyl halides), polyamides,cellulosic polymers, polyimides, acrylics, vinyl acrylics, styreneacrylics, polyvinyl alcohols, thermoplastic polyesters, thermosettingpolyesters, poly(phenylene oxide), poly(phenylene sulfide),polyvinylidene fluoride, poly(vinlyfluoride), ethylenechlorotrifluoroethylene copolymer, polyamide, phenolic resins,polyurethane, silicone polymers, and combinations thereof.
 3. Thecatalyst composition of claim 1, wherein the manganese oxide comprisescryptomelane, birnessite, vernadite, manganese oxide polymorph I, poorlycrystalline cryptomelane, amorphous manganese oxide, polymorphs thereof,or mixtures thereof.
 4. The catalyst composition of claim 1, wherein achloride content of the catalyst composition is less than 1 wt % basedon a total weight of the catalyst composition, or wherein a sulfatecontent of the catalyst composition is less than 1 wt % based on a totalweight of the catalyst composition.
 5. The catalyst composition of claim1, further comprising an inorganic oxide comprising one or more ofceria, zirconia, silica, titania, alumina, iron, lanthanum,praseodymium, samarium.
 6. An air filter comprising the catalystcomposition of claim 1, wherein the air filter is adapted for use in aportable air purifier, a heating, ventilation, and air conditioning(HVAC) system, a motor vehicle, a railed vehicle, a watercraft, anaircraft, or a spacecraft.
 7. A catalyst device adapted to remove one ormore of formaldehyde, ozone, carbon monoxide, nitrogen oxide, amines,sulfur compounds, thiols, chlorinated hydrocarbons, or volatile organiccompounds from an unpurified air supply, the catalyst device comprising:a housing; a substrate disposed within the housing, wherein thesubstrate is selected from a polymer substrate, a foam substrate, apaper substrate, a nonwoven filter, a paper filter, a fibrous filter, ora combination thereof; and a catalyst composition disposed in thehousing, wherein the catalyst composition comprises manganese oxide,bentonite from about 40 wt % to about 50 wt % based on a total weight ofthe catalyst composition, and a polymer binder comprisingpoly(tetrafluoroethylene), acrylic/styrene acrylic copolymer latex, or acombination thereof, wherein a BJH pore volume of the catalystcomposition ranges from about 0.3 mL/g to about 1.5 mL/g.
 8. Thecatalyst device of claim 7, wherein the polymer binder further comprisesa polymer selected from a group consisting of polyethylene,polypropylene, polyolefin copolymers, polyisoprene, polybutadiene,polybutadiene copolymers, chlorinated rubber, nitrile rubber,polychloroprene, ethylene-propylene-diene elastomers, polystyrene,polyacrylate, polymethacrylate, polyacrylonitrile, poly(vinyl esters),poly(vinyl halides), polyamides, cellulosic polymers, polyimides,acrylics, vinyl acrylics, styrene acrylics, polyvinyl alcohols,thermoplastic polyesters, thermosetting polyesters, poly(phenyleneoxide), poly(phenylene sulfide), polyvinylidene fluoride,poly(vinlyfluoride), ethylene chlorotrifluoroethylene copolymer,polyamide, phenolic resins, polyurethane, silicone polymers, andcombinations thereof.
 9. The catalyst device of claim 7, wherein themanganese oxide comprises cryptomelane, birnessite, vernadite, manganeseoxide polymorph I, poorly crystalline cryptomelane, amorphous manganeseoxide, polymorphs thereof, or mixtures thereof.
 10. The catalyst deviceof claim 7, wherein a chloride content of the catalyst composition isless than 1 wt % based on a total weight of the catalyst composition, orwherein a sulfate content of the catalyst composition is less than 1 wt% based on a total weight of the catalyst composition.
 11. The catalystdevice of claim 7, further comprising an inorganic oxide comprising oneor more of ceria, zirconia, silica, titania, alumina, iron, lanthanum,praseodymium, samarium.
 12. The catalyst device of claim 7, wherein thecatalyst device is incorporated into an air filter of a device selectedfrom a group consisting of: a portable air purifier, a heating,ventilation, and air conditioning (HVAC) system, a motor vehicle, arailed vehicle, a watercraft, an aircraft, and a spacecraft.
 13. Amethod of preparing a catalyst coating, the method comprising: mixingmanganese oxide, bentonite, and a polymer binder in water to form aslurry, the polymer binder comprising poly(tetrafluoroethylene),acrylic/styrene acrylic copolymer latex, or a combination thereof; anddepositing the slurry onto a substrate to form the catalyst coating onthe substrate, wherein the substrate selected from a polymer substrate,a foam substrate, a paper substrate, a nonwoven filter, a paper filter,a fibrous filter, or a combination thereof, wherein a BJH pore volume ofthe catalyst coating ranges from about 0.3 mL/g to about 1.5 mL/g,wherein the bentonite is present from about 40 wt % to about 50 wt %based on a total weight of the catalyst coating.
 14. The method of claim13, wherein the polymer binder further comprises a polymer selected froma group consisting of polyethylene, polypropylene, polyolefincopolymers, polyisoprene, polybutadiene, polybutadiene copolymers,chlorinated rubber, nitrile rubber, polychloroprene,ethylene-propylene-diene elastomers, polystyrene, polyacrylate,polymethacrylate, polyacrylonitrile, poly(vinyl esters), poly(vinylhalides), polyamides, cellulosic polymers, polyimides, acrylics, vinylacrylics, styrene acrylics, polyvinyl alcohols, thermoplasticpolyesters, thermosetting polyesters, poly(phenylene oxide),poly(phenylene sulfide), polyvinylidene fluoride, poly(vinlyfluoride),ethylene chlorotrifluoroethylene copolymer, polyamide, phenolic resins,polyurethane, silicone polymers, and combinations thereof.
 15. Themethod of claim 13, wherein the manganese oxide comprises cryptomelane,birnessite, vernadite, manganese oxide polymorph I, poorly crystallinecryptomelane, amorphous manganese oxide, polymorphs thereof, or mixturesthereof.
 16. A catalyst composition comprising: manganese oxidecomprising cryptomelane; bentonite from about 40 wt % to about 50 wt %based on a total weight of the catalyst composition; and a polymerbinder, wherein the catalyst composition is adapted to remove one ormore of formaldehyde, ozone, carbon monoxide, nitrogen oxide, amines,sulfur compounds, thiols, chlorinated hydrocarbons, or volatile organiccompounds from an unpurified air supply, and wherein a BJH pore volumeof the catalyst composition ranges from about 0.3 mL/g to about 1.5mL/g, wherein the catalyst composition is disposed on a substrateselected from a polymer substrate, a foam substrate, a paper substrate,a nonwoven filter, a paper filter, a fibrous filter, or a combinationthereof.